I don’t quite understand these two questions, anyone mind helping me out?

Which statement best explains why ben uses the width hi to create the arc at j from point k

At the beginning of 1974/75,2 years a man invested #2000 in a bank at 12.5% compound interest, if it degree #650 at the end of each two years to pay his son's school fees, after payment of interest to pay his son's school fees, how much did he have left at the beginning of the 1978/79 school year?

Solve each quadratic equation by factoring and using the zero product property. 10x + 6 = -2x^2 -2